Process and apparatus for bending metal bars



Jan. 9, 1934. w A. T. YATES PROCESS AND APPARATUS FOR BENDING METAL BARS Filed April 10, 1929 2 Sheets-Sheet l A rrozA/z K5.

Jan. 9, 1934- A. T. YATES 1,942,992

PROCESS AND APPARATUS FOR BENDING' METAL BARS Filed Aprii 10, 1929 r 2 Sheets-Sheet, 2

A Tra /v5 45.

Patented Jan. 9, 1934 UNITED STATES PROCESS AND APPARATUS FOR BENDING METAL BARS Arthur T. Yates, Buffalo, N. Y., assignor to Buffalo Forge Company, Buffalo, N. Y.

Application April 10, 1929. Serial No. 353,955

18 Claims.

This invention relates to improvements in processes and apparatus for bending metal bars of various cross sectional shapes into circles or arcs thereof.

Inlthe bending of angle bars for example, if thebar to be bent is so arranged that one flange extends oylindrically about the axis of curvature and--the other flange extends radially of or perpendicular to the axis of curvature and inwardly from the other flange towards said axis, the cross sectional shape of the bar is deformed in the passage of the bar through the bending rolls of the usual bending apparatus in such a manner that the circumferential flange does not extend at right angles to the radial flange and does not lie parallel with the axis of curvature. Also the bent bar will not remain in a plane perpendicular to said axis but tends-to assume a spiral formation. This is due to the fact that while the outer portions of the radial flange and the heel of the angle are stretched with consequent lengthening of the bar at these points, the free edge portion of the circumferential flange is not stretched and retains its original length.

In attempting to overcome this difficulty, ben d-+ ing machines or apparatus have been provided with guide rolls or other members disposed in the path of the leading end of the bars as they leave the bending rolls so as to engage the free edge of the circumferential flange of the angle or other bar and deflect the bar from its spiral course and force it into the desired plane perpendicular to the axis of curvature. The result however has not been entirely successful owing to the lack of the necessary stretching action upon said flange which it should receive in common with the other flange and the connecting portions of both flanges. Thus, while the bar is deflected by said guide means and in some cases a slight stretching or lengthening of the free edge portion of the circumferential flange may result, this flange nevertheless assumes an angular relation instead of a parallel relation to the axis of curvature.

Bars of this kind with a radial flange extending inwardly toward the axis of curvature from another flange have also been bent by subjecting the bars to two or more operations.

The objects of this invention are to provide a process and apparatus for bending flanged bars of this kind in such a manner that one flange thereof extends inwardly toward the axis of curvature from another flange and in which the bar can be correctly bent during a single operation or passthrough the apparatus; also to provide a method of bending angles and other flanged bars in such a manner, that should portions of a bar being bent assume a radius somewhat less than that ultimately desired, other portions of said bar so bent are being simultaneously bent to therequired curvature; also to provide bending apparatus of this kind with improved means for guiding the work into the bending rollsand with novel means acting upon the work after it leaves the bending rolls so that the bars will be bent in a plane perpendicular to the axis of curvature in a single operation; and also to construct such means so that lateral flanges or those flanges of the work which extend lengthwise of said axis of curvature will be bent so as to extend parallel with said axis.

Other objects are to improve processes of bending angles and other flanged metal bars, and apparatus for performing such processes in the other respects hereinafter setforth and claimed.

In the accompanying drawings:

Fig. 1 is a fragmentary front elevation of an improved bending machine or apparatus on which my novel process of bending angles and other flanged bars is carried out, showing my new attachment applied thereto, and an angle bar 50 being bent therein on a relatively large radius;

'- Fig. 2 is a fragmentary side elevation thereof;

Fig. 3 is a fragmentary face view thereof with the parts adjusted to bend an angle bar on a smaller radius than that shown in Fig. 1;

Fig. 4 is a fragmentary sectional plan view, on an enlarged scale on line 4--4, Fig. 1, showing the relation ofmy adjustable pressure finger or attachment to a guide roll or member of the apparatus;

Fig. 5 is a fragmentary sectional elevation thereof, on line 5-5, Fig. 4;

Fig. 6 is a fragmentary view on an enlarged scale showing an angle bar engaging the usual guide roll of the apparatus and illustrating the 5 distorted condition of the angle bar.

Fig. '7 is a similar view showing how the distortion of this angle bar is corrected by the use of the pressure finger or attachment.

Fig. 8 is a diagrammatic illustration showing 100 in full and. broken lines respectively, the relative positions of the circumferential flanges of an excessively bent angle bar before and after engaging the pressure flnger.

The bending apparatus or machine to which 105 my attachment may be applied for carrying out my improved process of bending angles and other bars may be of any suitable or desired construction. That shown in the drawings includes a frame or housing 10 having journalled therein 110 three shafts 11, 12 and 13, the ends of which project outwardly at the front of said housing and support three rotatable bending rolls 14, 15 and 16. The work is passed between the upper roll 14 and the two lower rolls 15 and 16, the former being adjustable toward and from the latter to effect the desired curvature of the work. Each of the rolls 14, 15 and 16 is formed in two parts, one at least of which is adjustable relatively to the other lengthwise of its shaft so as to provide a space for the reception of flanges of various thicknesses for guiding the work through the rolls.

The bending rolls are all driven at the same speed and in either direction, and when an angle bar A is passed between them, as from left to right, and with its flanges, a, a disposed as shown in Fig. 1, the bar is bent as illustrated in that figure.

The machine is also provided with the usual guide rolls or members 18, each of which is journalled in a bracket 19 mounted one at each side of the bending rolls. extend at right angles to the bending roll shafts, and each bracket 19 is supported on a stud shaft 20 arranged for axial sliding adjustment parallel with the axes of the shafts 11, 12 and 13 in a hole 21 in a lateral projection 22 of the housing 10, see Fig. 2. In this manner the rolls 18 can be positioned to intercept the edge of the flange a of the work and'deflect the bar as shown in Figs. 2, 6 and 7 thereby partly counteracting the tendency of the bar to assume a spiral form in an inward direction. The adjustment of the brackets 19 and rolls 18 for this purpose, however, is only suflicient to flex or stretch the bar slightly.

This adjustment of each bracket 19 may be effected by means of a screw 23 having threaded engagement in the stud shaft 20 and which is provided with a projecting handle 24 for turning it.

It is usual to provide means whereby the brackets 19 may be also turned about the axes of the supporting studs 20 so as to place the axes of the rolls 18 in different angular positions in accordance with the curvature of the work. The rolls 18 are rotated by the engagement of the work therewith and it is desirable to have the work cross the rolls substantially at right angles to reduce friction to a minimum. Suitable adjusting means are provided for this purpose such as'the spring pressed studs or pins 25 arranged in the projections 22 and each of which can be entered into any one of a series of holes 26 in a lug 27 of the corresponding bracket 19, see Figs. 1 and 3, to hold the bracket in adjusted position.

As thus far described the bending machine or apparatus is of known construction, of itself forming no part of this invention. It has been found, however, that the use of the guide rolls or members 18, while preventing the work from assuming an inwardly directed spiral helical form, nevertheless, due to the torsional strain applied to the bars by said guide rolls, together with the uneven stretching action given to the bar in the bending rolls causes the cylindrically disposed flange a of a bar to assume an angular relation to the axis of the rolls 18, as shown in Fig. 6.

' In order to overcome these objections, and the limitations in the use of the guide rolls in the manner described, novel means preferably used in conjunction with the guide rolls 18 are provided.

1 These means act on the laterally or cylindrically disposed flanges a of the-work in a manner to The axes of the rolls 18 and thus a helical formation of the finished product is prevented.

The means shown for this purpose comprise one or more attachmentseach having an adjustable pressure finger or member 30, two attachments being illustrated, and one of which is mounted on each bracket 19. Each finger is arranged so as to project downwardly and has a rounded free end 31 adapted to bear forcibly upon the lateral flange a of a bar leaving the bending rolls and offer such resistance to the twisting tendency of the work that the portions of the flange adjacent to the free edge thereof will be actually stretched by engagement with said face 31 of said finger 30.

The faces 31 preferably contact with the flanges a of the work adjacent to the portions of the rolls 18 contacting with the work. The fingers 30 are arranged for adjustment lengthwise of the rolls 18 to accommodate the fingers to different bending arcs. For this purpose each finger 30 is formed on or rigidly secured to a forwardly projecting arm 32 of a block 33. This block is slidably arranged for movement parallel with the axis of a roll 18 in a recess 34 in the corresponding bracket 19, with the arm 32 extending through a slot 35 connecting said recess with the exterior of said bracket. For adjusting the slidable block 33 the latter is formed with a longitudinal threaded hole 36 for the reception of an adjusting screw 3'7 extending through the recess 34 with its lower end projecting through a bottom wall 38 in said bracket 19. The'screw is prevented from endw-ise movement by collars 39 and is rotated by a suitable crank or handle 40 on its lower end.

In the use of an attachment for the purpose described its finger 30 after being adjusted with relation to a particular bar or piece of work so that its curved or cam face 31 is disposed in the path of the leading end a of the advancing bar. Thus the finger will intercept and forcibly deflect the free edge of the flange d downwardly, as illustrated in Fig. '7. This also slightly'turns or flexes the remaining portion of the bar, with the result that the bar is turned from its deformed or twisted position relatively to the axis of curvature shown in Fig. 6 to the position shown in Fig. 7 in which the flange a is at a right angle to the roll 18, that is parallel with the axis of curvature, and the flange a is truly perpendicular to this axis, and the bar, as it leaves the machine, as-

sumes the actual curvature desired after a single pass through the machine.

In actual practice therefore, the free edge of the circumferential flange of a bar or piece of work is bent by the bending rolls 14, 15 and 16 to a curvature of slightly less radius than that ultimately desired, and the finger 30 which is in the path of the advancing end of the work, regardless of which direction the work is being fed, is set so as to intercept, deflect and permanently bend or set the free edge of said flange of the work to the desired final radius or curvature.

When bending bars into circular form, as the leading end a approaches the other finger 30, that is the one at the opposite side of the apparatus this finger can be quickly adjusted to cause said end a to be directed or guided into the guide rolls and into engagement with or adjacent the other or trailing end a of the work.

When bending flanged bars to circular or arcuate form it sometimes happens that, due to improper adjustment of the bending rolls, or to variations in the stock, the work will be bent on a somewhat smaller radius than that intended. When this occurs in the use of bending apparatus not provided with my attachment having a pressure finger 30, the work can only be formed to the larger required are or radius by the use of a hammer or other tool. This, of course, precludes accurate results. However, by the provision of the pressure finger 30, the latter can be so adjusted outwardly relatively to the axis of curvature that the improperly bent work can be passed through the machine again, and the increased pressure of said finger on the lateral flange of the bar will stretch the work and the discrepancy corrected in a uniform and practical manner.

The adjustable pressure fingers also serve another important purpose in connection with the process of bending angle and other bars. Due to torsional strains set up by the bending rolls 14, 15 and 16 there is a tendency for the unbent or trailing portions of these bars to twist as these parts approach the bending rolls, so that with an angle bar for example, the heel of the bar is turned cornerwise upon the lower pair of rolls 15 and 16, and the work spoiled or deformed. However, by adjusting the appropriate finger 30 so as to bear upon the flange a of an angle or other bar after the latter has been initially engaged into the bending rolls, this flange will be held flat upon these rolls and the bar properly guided into said rolls and its tendency to twist overcome, as the flange a thereof is held parallel with the axis of curvature and to the axes of said bending rolls, see, Fig. 1.

By using both of the fingers 30 to hold the metal entering the bending rolls in correct position, as well as the metal leaving the rolls, incorrect bending of the work due to differences in hardness in the metal is prevented. It frequently happens that the bars which are being bent have soft spots therein, and when these soft spots are between the rolls, these portions of the bars would be bent to a curvature of shorter radius than other portions of the bars. By having both of the fingers 30 in engagement with the bar, thus forming a five point contact with the bar, unequal bending of the work is positively prevented, so that uniform curvatures are produced in all work regardless of variations in the hardness of the metal of the work.

Thus, by the addition'of the relatively simple and inexpensive attachments described to bending apparatus of the type heretofore used, greatly improved results are attained. The attachments are easily and quickly adjusted so as to cooperate with the bending rolls and the usual guide rolls, and work bent to the required form can be produced in less time than has heretofore been possible, since when the parts of the apparatus are properly adjusted, only a single pass of the work through the apparatus is necessary.

I claim:

1. The process for bending a metal bar having a flange extending parallel with the axis of intended curvature and another flange extending transversely thereof and inwardly towards said axis, which includes subjecting a bar to bending pressure in a set of bending rolls to bend the free edge of said first flange of said bar to a curvature of less radius than that ultimately required, and then subjecting said flange of said bar to further pressure to stretch the same to the required curvature.

2. The process for bending a metal bar having a flange extending parallel with the axis of intended curvature and another flange extending transversely thereof, which includes subjecting a bar to bending pressure in a set of bending rolls to bend the free edge of said first flange of said bar to a curvature other than that ultimately required, and simultaneously subjecting the bent portions of said first flange of the bar to further pressure to curve the same to the required radius while other portions of said bar are passing through said bending rolls.

3. The process of bending a metal bar having a flange extending parallel with the axis of in tended curvature and another flange extending transversely thereof, which includes subjecting a bar to bending pressure in a set of bending rolls to bend the free edge of said first flange of said bar to a curvature of less radius than that ultimately required, and simultaneously subjecting successive portions of that part of said first flange which has passed through said bending rolls to further pressure to stretch the same and increase the radius of curvature thereof to that required while other portions of said bar are passing through said bending rolls.

4. The process of bending a bar having a flange extending toward the intended axis of curvature and another flange extending from the outer portion of said flange at an angle thereto, including subjecting said bar to the bending action of a set of bending rolls, then exerting pressure in a plane transverse to the axes of said rolls on portions of said bar after leaving said rolls while other portions. of the bar are being acted upon by said rolls to correct deformation of the cross sectional shape of said bar by said bending rolls, and also exerting pressure in a plane transverse to the axes of said rolls on other portions of said bar passing to said rolls to correct deformation of the bar by the entry of the same into said rolls.

5. Apparatus for bending a flanged metal bar having a flange extending parallel with the axis of intended curvature and another flange extending transversely thereof, said apparatus including a set of bending rolls, and a stationary part disposed in the path of the bar as it leaves said rolls and which engages and stretches said first flange thereof in an outward direction relative to said axis of curvature and causes said bar to assume the required curvature.

6. Apparatus for bending a flanged metal bar having a flange extending parallel with the axis of intended curvature and another flange extending transversely thereof, said apparatus including a set of bending rolls to bend a bar about an axis of curvature, said rolls being adjustable to bend the work to different curvatures, and a stationary part disposed in the path of said bar so as to engage a face of said first flange of said bar after the latter leaves said rolls to hold said flange in parallel relation to the axis of curvature, said stationary part being adjustable to engage bars of different curvature.

'7. Apparatus for bending a flanged metal bar having a flange extending parallel with the axis of intended curvature and another flange extending transversely thereof and inwardly towards said axis, said apparatus including a set of bending rolls to bend a bar about an axis of curvature, said rolls being adjustable to bend the work to different curvatures, a guide member disposed so as to engage the edge of said first flange of said bar after the latter has left said bending rolls to deflect the same parallel with said axis and in a direction towards said other flange, and a stationary part associated with said guide member to engage the free edge of said first flange and deflect the latter in an outward direction with relation to the axis of curvature whereby deformation of said bar incident to its passage through said bending rolls is corrected.

8. Apparatus forbending a flanged metal bar having a flange extending parallel with the axis of intended curvature and another flange extending transversely thereof and inwardly towards said axis, said apparatus including a set of bending rolls to bend a bar about an axis of curvature, said rolls being adjustable to bend, the work to different curvatures, a bracket, a guide member on said bracket engageable with an edge of said first flange of said bar to deflect the same parallel with said axis and in a direction towards said other flange, said bracket being adjustable to position said guide member in engagement with flanges of different widths and for engaging work of diiferent curvatures, a slide mounted on said bracket and having a part engageable with the inner face of said first flange adjacent the free edge thereof for deflecting said flange in an outward direction relative to the axis of curvature, said slide being adjustable on said bracket to position said flange engaging part for engagement with work of different curvatures.

9. Apparatus for bending a flanged metal bar having a flange extending parallel with the axis of intended curvature and another flange extending transversely thereof and inwardly towards said axis, said apparatus including a set of bending rolls to bend a bar about an axis of curvature, said rolls being adjustable to bend the work to different curvatures, means disposed at one side of said bending rolls in the path of and engageable with the freeedge of said first flange of said bar after the bar leaves said rolls for deflecting said bar laterally to correct deformation of said bar incident to thebending operation and to stretch said flange radially to the desired curvature, and means disposed 'atthe opposite side of said bending rollsrand engageable with said first flange of said barto hold the bar in operative relation to said bending rolls as it enters said rolls.

10. Apparatus for bending a flanged metal bar having a flange extending parallel with the axis of intended curvature and another flange extending transversely thereof and inwardly towards said axis, said apparatus including a set of bending rolls to bend a bar about an axis of curvature, a member at one side of said bending rolls engageable with said first flange of said bar after the latter leaves said bending rolls and which exerts pressure thereon in z: direction perpendicular to said axis to hold said flange in parallel relation to said axis of curvature, and'a second member at the opposite side of said bending rolls which is engageable with said flange of said bar in a like manner to hold the bar in operative relation to said bending rolls as it enters said rolls, said members being adjustable for engagement with work to be bent on different curvatures.

11. The process of bending a metal bar having a flange extending parallel with the axis of intended curvature and another flange extending be attained, and exerting bending pressure on transversely thereof and inwardly toward said axis, which includes subjecting a bar to bending pressure in a set of bending rolls to curve the bar in a direction enabling the flnal form desired to said first flange at opposite sides of said bending rolls in a direction away from the axis of curvature, onportions of the bar which have passed out of contact with said bending rolls.

12. The process of bending bars into curved forms, includingsubjecting the bars to the action of a bending machine having rolls spaced so that one roll exerts pressure on the bar at a point intermediate of the other rolls, and exerting bending pressure against said bar at opposite sides of said rolls and in a direction opposing said two rolls on portions of the bar which have passed out of contact with said bending rolls.

13. In an angle iron bending machine, co-op-' erative rollers arranged to engage and to feed one of the flanges between them, one of the rollers having an annular groove for receiving the other flange, and a side plate having a bearing surface adapted to be engaged by the free edge of the first named flange as the angle iron is fed beyond the rollers for holding the bent portion of the angle iron in a plane parallel with that of the annular groove, said side plate being provided with a bearing member engaging the concave face of the first named flange to assure a uniform curvature of 05 said flange.

14. In an angle iron bending machine, co-operative feeding rollers having parallel axes arranged at the angles of a triangle for engaging opposite faces of one of the flanges and feeding the angle iron endwise, one of said rollers having an annular groove for receiving the other flange of the angle iron, guide plates arranged at opposite sides of the grooved roller for engagingthe free edge of the first named flange, each guide plate being provided with a bearing member for engaging one of the faces of said first named flange.

15. In a machine for bending metal bars, a set of parallel rollers for feeding and bending the bar, a bearing member exerting pressure on said bar in a direction transversely to the axis of the rollers, a second bearing member exerting pressure on said bar in the direction of the axes of the rollers, and a third bearing member on the second bearing member exerting pressure on the bar transversely of said axes.

16. In a machine for bending metal bars, a set of parallel rollers for feeding and bending the bar, bearing plates at opposite sides of the rollers exerting pressure on the bar in a direction parallel with said rollers, and bearing members on said plates exerting pressure on the bar transversely of said axes.

17. In a machine for bending metal bars, a set of parallel rollers for feedingand bending the bar, bearing plates at opposite sides of the rollers exerting pressure on the bar in a direction parallel with said rollers, and bearing members on'said plates exerting pressure on the bar transversely of said axes, and means for adjusting said plates transversely of said axes to vary the pressure of said members on the bar.

18. In a metal bending machine, co-operative rollers arranged to engage and to feed said metal 45 between them, a side plate adjustable about an axis parallel with the axes of the rollers, and a bearing member eccentrically mounted on said plate for engaging one of the faces of said metal.

ARTHUR T. YATES. 

